1. Technical Field of the Invention
This invention pertains to integrated circuit (xe2x80x9cICxe2x80x9d) chips and an apparatus and method for evaluating their performance. In particular, this invention provides a ring oscillator circuit built into an IC chip. The circuit includes a single input/output (xe2x80x9cI/Oxe2x80x9d) used for activating and monitoring the circuit in order to evaluate a performance level of the IC chip.
2. Background Art
Related prior art circuit designs require two pins for activation and monitoring.
This invention pertains to an apparatus and method for evaluating performance of an IC. An advantage of the present invention includes determining whether manufacturing or process variations have caused performance of an IC to deviate out of spec. The invention provides a single I/O oscillator circuit on a chip whose output generally corresponds to a performance level of the IC chip, thereby providing an easy access and testing method for evaluating chip performance. The I/O point is used for coupling to the circuit, activating the circuit, and monitoring its oscillating output signal. The single I/O point may be accessed at the wafer level, after packaging (via an I/O pin on a module, for example), in the field, or at any point between manufacture and end use.
It is an object of the invention to screen IC products based on performance by providing a screening apparatus activated and monitored with a single pin, immune to harmonic generation, and whose oscillation is not a function of the load.
Other features and advantages of this invention will become apparent from the following detailed description of the presently preferred embodiment of the invention, taken in conjunction with the accompanying drawings.